The invention relates to a fuel tank connector for connecting a fuel tank having an outer surface made of a synthetic resin and various types of pipe.
A connector is used for connecting a fuel tank and an internal combustion engine. This type of connector includes a flange portion for closing a connecting opening provided in the fuel tank from outside the fuel tank, and an outer connecting portion to be connected to various pipes for transferring fuel gas or the like.
The fuel tank with the outer surface made of a synthetic resin has been widely used. In such a fuel tank, the connector made of the same synthetic resin can be easily fixed to the outer surface of the fuel tank by heat-fusing an outer peripheral portion of a flange contacting the outer surface of the fuel tank.
In fixing, i.e. welding to fit the connector firmly, it is necessary to form at least a portion where the connector is welded, with the same synthetic resin as that formed in the outer surface of the fuel tank.
A high-density polyethylene has been widely used to form the outer surface of the fuel tank. However, since the polyethylene has high fuel gas permeability, it is not desirable to make the whole connector with the same synthetic resin as that of the outer surface of the fuel tank.
A casing member for receiving therein, for example, a float constituting a float valve may be connected to a portion of the connector to be inserted into the fuel tank through the connecting opening provided in the fuel tank. In this case, it is possible to provide the connector with a function as the float valve. Further, the case and connector may be provided with engaging portions for engaging each other. The connector itself is a single part, and a casing member for constituting various functional members, for example, can still be connected to the connector. However, in this case, when the whole connector is made of the same synthetic resin as that of the outer surface of the fuel tank, the engaging portion between the case and connector can not be stably secured since polyethylene has relatively low rigidity and is easy to swell by the fuel.
Therefore, an object of the invention is to provide a connector, wherein the connector can be easily welded well to the fuel tank with the outer surface made of a synthetic resin.
Another object of the invention is to provide a connector as stated above, wherein a leakage of the fuel gas can be effectively prevented, and an engaging portion of components disposed in the fuel tank can be stably held.
Further objects and advantages of the invention will be apparent from the following description of the invention.